Add a instance variable to the family called 'id'. Set the id of the sword to 1 (and I assume you have other weapons? So for each of them you give another id) you can do this by just selecting the sword, you don't need events.
Then on the events do this:
Condition: Player collides with FamilyWeapons
>Sub-Event: FamilyWeapons.id = 1
>>Result: Do actions, because you picked the sword, eg: destroy FamilyWeapons (this will destroy only the sword, because the sub-event picked only the object with id = 1)
>Sub-Event: FamilyWeapons.id = 2
>>Result: Do actions, because you picked the bow